1. Field of the Invention
The present invention relates to a cleaning system using cleaning balls to clean condenser tubes and, more particularly, to a condenser tubes cleaning system providing a bypass flow function for reducing the electrical power load of the main circulating pump.
2. Description of the Related Prior Art
There are some prior arts, such as four cleaning systems described in patent documents U.S. Pat. Nos. 5,176,204, 5,592,990, 6,070,652, and 7,036,564. A condenser tubes cleaning system described in U.S. Pat. No. 7,036,564 shown in FIG. 5, comprises a flow diverter 11, a ball trap 12, a ball barrel 17, a first normally closed two-way valve V10, and a second normally closed two-way valve V20. The ball barrel 17 contains a number of cleaning balls 16 having a diameter slightly larger than the diameter of the condenser tubes. A condenser 15 is located between the main supply pipe 13 and the main return pipe 14. Thus, when the main circulating pump (not shown) is running and the first normally closed two-way valve 10 is open, the flow diverter 11 and the ball trap 12 create a (static) differential pressure to push the cleaning balls 16 out of the ball barrel 17 to flow through the main supply pipe 13 into the condenser 15 to remove dirty substances or slimes clung on the inner tubes 150 of the condenser 15. However, the first normally closed two-way valve V10 and the second normally closed two-way valve V20 are always closed during the long standby period, i.e. before the cleaning balls 16 are pushed out of the ball barrel 17.
The common disadvantage of all these prior arts is the flow diverter 11 and the ball trap 12 do not have a bypass flow function to relieve the pressure drops in the flow diverter 11 and the ball trap 12 during the long standby period, so that the unrelieved pressure drops become the electrical power load of the main circulating pump, namely the main circulating pump shall consume extra electrical power.